The present invention relates to a fluid pressure device having a reversible mounting mechanism by which the device can be mounted to a predetermined position on either one of two side faces facing each other through a bolt.
As one of fluid pressure devices, there is a dual-rod-type air cylinder, for example, in which two cylinder mechanisms 2a and 2b having pistons 2 and rods 3 are mounted in a casing 1 in a shape of a flat and short prism, the two rods 3, 3 projecting from the casing 1 are connected to a common plate 5, and a workpiece 6 is driven by the two rods 3, 3 through the plate 5 as shown in FIGS. 6 and 7. In this air cylinder, in order to detect operating positions of the pistons 2 to produce control signals for automatic operation, sensor mounting grooves 7 are formed in positions close to cylinder bores in the casing 1 and position sensors 8 are mounted in the mounting grooves 7. In order to fix the air cylinder to a predetermined position through bolts 9, fixing holes 10 are formed in the casing.
In such an air cylinder, there is no problem if the fixing holes 10 are formed in such positions as not to overlap the sensor mounting grooves 7. However, if the fixing hole 10 and the sensor mounting groove 7 are formed in such positions as to overlap one another as shown in FIGS., it is necessary to apply deep spot-facing processing 10a such that bolt head 9a is in a position lower than the sensor mounting groove 7 so as to prevent the bolt head 9a positioned on the sensor mounting groove 7 from obstructing mounting of the position sensor 8.
If the air cylinder needs to be able to be fixed on either one of left and right side faces, it is necessary to form the sensor mounting grooves 7 in the opposite side faces of the casing 1 and to apply the deep spot-facing processing 10a described above to each ends of the fixing hole 10 such that the bolt 9 can be inserted from either face to fix the air cylinder. However, in a case of a small air cylinder in which diameters of the pistons 2 and a thickness of the casing 1 are small, because a gap between the two sensor mounting grooves 7, 7 in the opposite side faces is small, it is impossible to apply deep spot-facing processing 10a to the opposite ends of the fixing hole 10.
It is a technical object of the present invention to provide a fluid pressure device having mounting grooves into which an accessory part such as a sensor is mounted and a fixing hole for fixing the device by a bolt, the mounting grooves and the fixing hole being formed in positions overlapping each other, wherein the fluid pressure device can be fixed by the bolt on either one of two side faces facing each other of the device by providing a reversible mounting mechanism with a simple structure without applying deep spot-facing processing for preventing interference with the accessory part to opposite ends of the fixing hole.
To achieve the above object, in a fluid pressure device of the present invention, a casing having mounting grooves for accessory parts respectively on a first face and a second face facing each other of the casing is formed with a fixing hole for fixing the fluid pressure device by a bolt such that the fixing hole passes through the casing between the opposite faces in a position which overlaps the mounting grooves, a washer member for forming a seat with which a bolt head is brought into contact is housed in the fixing hole such that the washer member can be moved to a first face side and a second face side, and the washer member has such an axial length that the washer member and the bolt head do not interfere with the mounting groove cut in the face on the other side when the washer member has moved to any one of the opposite face sides.
In the fluid pressure device having the above structure, when the second face of the casing is brought into contact with a portion to which the device is mounted and the bolt is inserted into the washer member in the fixing hole from the first face side to fix the fluid pressure device, the washer member is moved to the second face side and the device is fixed by the bolt in this state. At this time, because both the washer member and the bolt head are in lower positions than the mounting groove in the first face side and do not interfere with the mounting groove, the accessory part such as the position sensor can be mounted into the mounting groove without hindrance.
On the other hand, when the first face of the casing is brought into contact with a portion to which the device is mounted and the bolt is inserted into the fixing hole from the second face side to fix the fluid pressure device, the washer member is moved to the first face side. At this time, because both the washer member and the bolt head do not interfere with the mounting groove on the second face side, the accessory part such as the position sensor can be mounted into the mounting groove without hindrance.
Thus, according to the invention, it is possible to reversibly mount even the small fluid pressure device with a small thickness to a predetermined position on either one of the two side faces facing each other of the device by a remarkably simple structure in which the annular washer member is housed for movement in the fixing hole without applying deep spot-facing processing for preventing interference with the accessory part to the opposite ends of the fixing hole.
According to a concrete embodiment of the invention, the washer member has an annular and inward flange forming the seat in a tube portion.
According to a preferred embodiment of the invention, an inner peripheral face of the fixing hole and an outer peripheral face of the washer member are respectively threaded and the washer member is screwed into the fixing hole such that a position of the washer member can be adjusted by rotation.
According to another concrete embodiment of the invention, the fluid pressure device is a dual-rod-type air cylinder and has two cylinder bores formed in parallel to each other in the casing, pistons which can slide in the respective cylinder bores, and rods extending from the respective pistons. The mounting grooves are the mounting grooves into which the position sensor for detecting an operating position of the piston is mounted and are formed along one of the two cylinder bores in positions facing each other at central portions on the opposite faces of the casing.